Infiltration of Helicobacter pylori in the gastric mucosa.

It is our hypothesis that if Helicobacter pylori could be demonstrated conclusively to have transgressed the mucosal surface into the lamina propria, this would help explain how H pylori recruits inflammatory cells. We report our immunohistochemical and electron microscopic findings that demonstrate that H pylori can be detected in the lamina propria of the stomach, offering evidence of its invasive potential. We stained 67 endoscopic gastric biopsy specimens with Warthin-Starry silver and immunoperoxidase stains for H pylori. In addition, transmission electron microscopy was performed on 1 case. The presence of surface H pylori was associated significantly with active (P < .0001) and chronic (P < .0001) inflammation. H pylori could not be identified in the lamina propria using the Warthin-Starry silver stain alone. Immunoreactivity for H pylori in the lamina propria was detected in 20 (30%) of 67 gastric biopsy specimens. Transmission electron microscopy confirmed the immunohistochemical findings. H pylori can infiltrate the lamina propria of the gastric mucosa, thereby proving morphologic evidence of its invasive capability.